用个sum储存和,枚举每一个元素然后累加就好了。

#include<iostream>
#define int long long
using namespace std;
int n,a,sum;
signed main(){
	cin>>n;
	for(int i=1;i<=n;i++)cin>>a,sum+=a;
	cout<<sum;
	return 0;
}

//C语言 #include <stdio.h>

int main() { int n; scanf("%d", &n); int a = 0; int sum = 0; int b;

while (a < n) {
	scanf("%d", &b);
	sum += b;
	a++;
}
printf("%d", sum);
return 0;

}

#include <stdio.h> int main() { int n; int i; int m; long long sum=0; scanf("%d",&n);

for(i=1;i<=n;i++){
	scanf("%d",&m);
	sum+=m;
}
printf("%lld",sum);

return 0;

}